Product inventories are warehoused where they can be quickly and efficiently stored and retrieved to accommodate marketing and consumer demands. Warehouse storage rack structures having a plurality of rows of vertically stacked bays are used to store pallets supporting containers, cartons, or products. Each bay has rail assemblies providing parallel tracks for the wheels of carts carrying the pallets. Examples of warehouse storage rack structures having movable carts for carrying pallets are described in the following U.S. Patents.
E. Doring in U.S. Pat. No. 4,341,313 discloses a pallet shelving structure having inclined rails accommodating carriages for supporting pallets. The pallets are loaded and unloaded from the carriages at one end of the rails to reduce the passageway area required for using the shelving structure.
T. Scott et al in U.S. Pat. No. 5,393,188 discloses a pallet storage system having rectangular rails and U-shaped carts. The rails have top surfaces for cart wheels which ride on inner and outer top edges of the rails. The carts are sized so that carts overlap each other when located in the loading positions of the carts.